I begin downloading the Shogun 2 patch (a massive one) and everything goes fine. The patch downloads at a constant 1.1-1.3 MB/s but after about 5 minutes, download speeds drop to 75 KB/s and then drop until the download stops in its tracks.

Oddly enough, if I start another download in Steam (such as the Mass Effect purchase I did a few weeks ago) the Shogun patch begins downloading again. If I pause the Mass Effect download, the Shogun one boosts up to full speed....for about 5 minutes before dropping off.

Has anyone else experienced this or heard of any similar issues? I have gone through the Steam forums and there were some instances of this happening but no good solution was ever posted.

I have had this issue before where I basically had to pause and unpause the download to get it working. It was during the first day of a game (which I can't remember) so the server may have been over capacity or something. Did the shogun 2 patch come out today?

I've run into this as well, I just attributed it to server load balancing because of people playing games (usually happened between ~4 - 7pm EST, I just assumed that it was quite a few people getting home from work/school and logging on).

YUp, server loads, and I never pause d/l in steam anymore, and I only try to do one at a time now. I find logging out and back in and let it initialize on its own works best.
You can check your content server location in the settings menu, and see if it's near you. I found if I've deleted clientregistry.blob for troubleshooting, steam automatically puts my content server to one that is not the closest to me, but it likely didnt make much difference in my case.